Canadian Cardiovascular Society Atrial Fibrillation Guidelines 2010: Surgical Therapy
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Surgery for atrial fibrillation (AF) has been demonstrated as an effective treatment to restore and maintain sinus rhythm in patients for whom a rhythm control strategy is desired. It is usually offered to patients undergoing other types of cardiac surgery (eg, mitral valve repair or replacement, coronary artery bypass grafting, aortic valve surgery, intracardiac defects, ascending aortic surgery). It is also feasible as a stand-alone procedure, bearing a high success rate. In the past few years, less-invasive procedures have been described. AF is a triggered arrhythmia, resulting from ectopic activity most commonly located in and around the pulmonary veins of the left atrium. Therefore, electrical isolation of the pulmonary veins from the rest of the left atrium in order to prevent AF from being triggered is the rationale common to all surgical techniques. Further substrate modification may be required in patients with more persistent AF. This is done by adding ablation of the posterior left atrium with connecting lines of block between pulmonary veins, to the mitral valve annulus, as well as in specific sites in the right atrium. The left atrial appendage is resected or occluded at the same time. Despite patients' high rate of freedom from AF after surgery (70%-85% at 1 year), surgical ablation of AF has never been clearly shown to alter long-term mortality. The available literature supports the recommendation to stop oral anticoagulation therapy 6 months after surgery when sinus rhythm can be documented, because a very low rate of thromboembolic events is reported. However, there is no evidence-based data to support the safety of omitting long-term oral anticoagulation. Thus, surgery should be used primarily as a concomitant procedure during cardiac surgery for other diseased states or as a stand-alone procedure after failure of prior attempts of catheter ablation and antiarrhythmic drugs.
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